Generally, an engine is a device that converts thermal energy into a mechanical rotational force by rotating a crankshaft through a connecting rod connected to a piston with explosive power generated by combustion of fuel in a combustion chamber formed between a bore of a cylinder block and the piston reciprocating in a cylinder head and the bore.
In a compression stroke and an explosion stroke of an engine, gas leaked from a gap between a cylinder and a piston to a crankcase contains components such as hydrocarbon and a nitrogen compound which are harmful to a human body. Environmental pollution is caused in a case where the leaked gas is emitted into the atmosphere, therefore emission of blow-by gas such as a fuel-air mixture of combusted gas and non-combusted gas into the atmosphere has been strictly regulated. The blow-by gas indicates gas leaking into a cylinder head or a crankcase while obtaining power by compressing and exploding fuel in a combustion chamber.
For this reason, the blow-by gas which is leaked from the cylinder into the crankcase is recirculated to an intake system, supplied to the cylinder along with an intake, and is emitted into the atmosphere through an exhaust emission control device of an exhaust system.
Accordingly, the blow-by gas flows into the combustion chamber, thereby re-combusted.
FIG. 1 is a perspective view illustrating a breather hose of an engine in the related art.
Referring to FIG. 1, a breather hose 52 that sends blow-by gas leaking into a rocker cover 50 to an intake manifold 51 again to flow in the combustion chamber is illustrated.
The breather hose 52 serves to prevent air pollution due to the emission of the blow-by gas into the atmosphere by supplying the blow-by gas leaking into the cylinder head again through the intake manifold 51 to the combustion chamber, as described above.
Such an exhaust gas circulating system of a diesel engine increases a temperature of an intake by mixing external air taken into the intake system and the circulated blow-by gas in the exhaust system, thus the system can improve engine efficiencies and an emission problem.
Meanwhile, in a case where non-coupling or burning of the breather hose occurs, air pollution is caused due to the emission of the blow-by gas into the atmosphere, therefore a diagnostic device and a diagnostic method of a non-coupling breather hose have been required.